Not Applicable.
1. Field of the Invention
This invention relates to flexible heating and cooling devices in which an electric current provides the power for heating and cooling.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
U.S. Pat. No. 4,388,607 discloses conductive polymer compositions made of carbon black dispersed in a crystalline copolymer. The use of such compositions in self-regulating heaters was disclosed.
U.S. Pat. No. 4,764,664 discloses a process for reducing the contact resistance between an electrode and a conductive polymer composition, thereby increasing the stability of a heating device constructed of such a polymer and electrodes. In the process, the electrode is heated to a temperature above the melting point of the composition before contacting the composition.
U.S. Pat. No. 4,777,346 discloses a liquid or gel filled pillow containing a resistance heater which is activated when a person compresses a switch formed of a layer of non-conductive foam located between two conductive layers.
U.S. Pat. No. 4,907,340 discloses a method for increasing the stability of a conductive polymer composition, which consists of cross-linking the composition using irradiation.
U.S. Pat. No. 5,111,032 discloses a self-regulating strip heater made of conductive polymer with embedded electrodes surrounded by a strengthening braid. The thermal efficiency of the heater is increased by impregnating the interstices of the braid with an outer insulating layer.
U.S. Pat. No. 5,653,741 discloses a flexible pad for heating or cooling a body part which has thermoelectric devices attached to a thermal conductive material. The thermoelectric devices heat or cool depending on the polarity of the current which power them. An enclosure surrounds the thermoelectric devices and fans are used to cool the heat sink portion of the thermoelectric devices when used to cool the body part.
The KA SMARTEST heating pad has an electronic control connected by a wire to the pad which provides four temperatures settings and automatic shutoff after 30 minutes. The heating pad has a cloth cover with a strap to secure the pad in place and a moistening sponge pad. KA SMARTEST is a trademark for a heating pad obtainable from Comfort House, Newark, N.J.
The prior art does not disclose the heater or cooler of this invention in which a flexible conformal container loaded with thermally conductive material is heated by a PTC heater or cooled by a thermoelectric device mounted on the outside of the container. The heater or thermoelectric device is powered by low voltage direct current which is controlled by a controller in response to the temperature of the thermally conductive material in the container as sensed by a thermoelectric device sensor.
This invention is a flexible heater or cooler which includes a flexible, conformal, thermally conductive container filled with thermally conductive material. A thermal element within the container or in contact with the outside of the container provides heat to the container or removes heat from the container. The thermal element is powered by a low voltage direct current electrical source. A sensor for determining the temperature of the thermally conductive material is also included. The thermal element, electrical source, and sensor are in communication by connectors with a solid state continuous temperature controller. In operation, the electrical source provides power to the thermal element, thereby heating or cooling the thermally conductive material within the container. The temperature in the container is determined by the sensor and the controller controls the power delivery to the thermal element in response to the setting on the controller and the temperature in the container.
The objective of this invention is to provide a flexible, conformal heater or cooler for application to sore or distressed areas of the body.
Another objective is to provide a heater for regulated industrial heating or cooling applications.
Another objective is to provide a heater with provisions to prevent overheating.
Another objective is to provide a heater or cooler which is powered by low voltage direct current electricity.
Another objective is to provide a heater or cooler which does not emit ENF radiation.
Another objective is to provide a heater which inherently limits the maximum temperature attainable.
Another objective is to provide a heater which avoids the hazards of accidental electrical shock.
Another objective is to provide a heater or cooler with user control of the temperature.
A final objective is to provide a flexible conformal heater or cooler which is constructed easily and inexpensively of common materials and whose manufacture and use is without adverse effects on the environment.